1,440 research outputs found
Direct Measurement of Periodic Electric Forces in Liquids
The electric forces acting on an atomic force microscope tip in solution have
been measured using a microelectrochemical cell formed by two periodically
biased electrodes. The forces were measured as a function of lift height and
bias amplitude and frequency, providing insight into electrostatic interactions
in liquids. Real-space mapping of the vertical and lateral components of
electrostatic forces acting on the tip from the deflection and torsion of the
cantilever is demonstrated. This method enables direct probing of electrostatic
and convective forces involved in electrophoretic and dielectroforetic
self-assembly and electrical tweezer operation in liquid environments
Oxidation and chemical state analysis of polycrystalline magnetron sputtered (Ti,Al)N films at ambient and liquid N-2 temperatures
In order to improve the functional properties of hard coatings, recent investigations have been directed towards Ti-N based multicomponent materials. The nitride (Ti, Al)N, in particular, with a Ti:Al ratio of 1:1 seems to be a promising alternative to the widely used TiN, exhibits better oxidation resistance and hence improved performance over that of TiN. (Ti, Al)N coatings were de sputter deposited onto 316SS substrates under ambient and liquid nitrogen temperatures. As deposited films were oxidized in a vertical fused-silica tube furnace in pure O-2 flowing atmosphere at temperatures ranging from 700 to 900 degrees C. Scanning electron microscope and atomic force microscope images reveal information about the particle size and film thickness. X-ray photoelectron spectroscopy was employed to study the chemistry of the cop few atomic layers in addition to compositional analysis and information on the details of chemical bonding, The difference in film stoichiometry are compared at two different deposition conditions thus reflecting their behavior under oxidizing conditions
Fabrication, Dynamics, and Electrical Properties of Insulated SPM Probes for Electrical and Electromechanical Imaging in Liquids
Insulated cantilever probes with a high aspect ratio conducting apex have
been fabricated and their dynamic and electrical properties analyzed. The
cantilevers were coated with silicon dioxide and a via was fabricated through
the oxide at the tip apex and backfilled with tungsten to create an insulated
probe with a conducting tip. The stiffness and Q-factor of the cantilevers
increased after the modifications and their resonances shifted to higher
frequencies. The coupling strength between the cantilever and the coating are
determined. The applications to conductive and electromechanical imaging of
ferroelectric domains are illustrated, and a probe apex repair process is
demonstrated.Comment: 3 fig
Adoption of Rational Farming Technology for Development of a Model for Exploring Sustainable Farming Practice in Farmer’s Field
The effectivity of Inhana Rational Farming (IRF) Technology was critically evaluated as a model of Sustainable Farming Practice in farmers’ field using okra (variety : Shakti - F1 hybrid) as test crop. The stusy was conducted at Binuria village in Birbhum District of West Bengal during February to October (2013). The village is in close vicinity of Visva Bharati University, Santiniketan. The study area lies in 23.660 N and 87.630E at about 179 ft. above MSL, with level to nearly level landscape. The experiment was laid down as per randomized block design (RBD) with 7 treatments replicated 3 times. The treatments included local farming practice with chemical inputs, organic farming practice (Inhana Rational Farming (IRF) Technology’ developed by Dr. P. Das Biswas, Founder, Inhana Biosciences, Kolkata) as well as integrated farming practice (combination of chemical and organic inputs for both soil and plant management). The most significant finding was that 100% reduction of chemical pesticide can be economically viable in the very first year with adoption of IRF Organic Package of Practice, under which 13.6% yield increase was recorded as compared to conventional farmer’s practice. Also when IRF was adopted for integrated cultivation model, higher yield as well as higher net income was obtained in comparison to conventional Farmer’s practice. Upto 144.5% higher Nitrogen Utilization efficiency and 32.8 % higher partial factor productivity was recorded under treatments with IRF Package. This higher response might be due to increased uptake and utilization of indigenous nutrients under the influence of high quality Novcom compost containing huge population (in order of 1016 c.f.u per gm moist compost) of self- generated microbes, which led to better nutrient (both macro and micro) mineralization in soil for plant uptake. This was also complimented by IRF Plant Management Package, which perhaps enhanced plant physiological functioning in terms of better N uptake and its utilization within plants
Comparing alkylresorcinols and mammalian lignans as biomarkers of wholegrain wheat or wholegrain rye intake in a dose-response intervention trial: the Grain Mark Study
Neuroimaging in cannabis use: a systematic review of the literature
Background We conducted a systematic review to assess the evidence for specific effects of cannabis on brain structure and function. The review focuses on the cognitive changes associated with acute and chronic use of the drug. Method We reviewed literature reporting neuroimaging studies of chronic or acute cannabis use published up until January 2009. The search was conducted using Medline, EMBASE, LILACS and PsycLIT indexing services using the following key words: cannabis, marijuana, delta-9-tetrahydrocannabinol, THC, cannabidiol, CBD, neuroimaging, brain imaging, computerized tomography, CT, magnetic resonance, MRI, single photon emission tomography, SPECT, functional magnetic resonance, fMRI, positron emission tomography, PET, diffusion tensor MRI, DTI-MRI, MRS and spectroscopy. Results Sixty-six studies were identified, of which 41 met the inclusion criteria. Thirty-three were functional (SPECT/PET/fMRI) and eight structural (volumetric/DTI) imaging studies. The high degree of heterogeneity across studies precluded a meta-analysis. The functional studies suggest that resting global and prefrontal blood flow are lower in cannabis users than in controls. The results from the activation studies using a cognitive task are inconsistent because of the heterogeneity of the methods used. Studies of acute administration of THC or marijuana report increased resting activity and activation of the frontal and anterior cingulate cortex during cognitive tasks. Only three of the structural imaging studies found differences between users and controls. Conclusions Functional neuroimaging studies suggest a modulation of global and prefrontal metabolism both during the resting state and after the administration of THC/marijuana cigarettes. Minimal evidence of major effects of cannabis on brain structure has been reporte
Rainfall, not soil temperature, will limit the seed germination of dry forest species with climate change.
Drylands are predicted to become more arid and saline due to increasing global temperature and drought. Although species from the Caatinga, a Brazilian tropical dry forest, are tolerant to these conditions, the capacity for germination to withstand extreme soil temperature and water deficit associated with climate change remains to be quantified. We aimed to evaluate how germination will be affected under future climate change scenarios of limited water and increased temperature. Seeds of three species were germinated at different temperatures and osmotic potentials. Thermal time and hydrotime model parameters were established and thresholds for germination calculated. Germination performance in 2055 was predicted, by combining temperature and osmotic/salt stress thresholds, considering soil temperature and moisture following rainfall events. The most pessimistic climate scenario predicts an increase of 3.9 °C in soil temperature and 30% decrease in rainfall. Under this scenario, soil temperature is never lower than the minimum and seldomly higher than maximum temperature thresholds for germination. As long as the soil moisture (0.139 cm3 cm3) requirements are met, germination can be achieved in 1 day. According to the base water potential and soil characteristics, the minimum weekly rainfall for germination is estimated to be 17.5 mm. Currently, the required minimum rainfall occurs in 14 weeks of the year but will be reduced to 4 weeks by 2055. This may not be sufficient for seedling recruitment of some species in the natural environment. Thus, in future climate scenarios, rainfall rather than temperature will be extremely limiting for seed germination
Lobular carcinoma in situ of the breast is not caused by constitutional mutations in the E-cadherin gene
Lobular carcinoma in situ (LCIS) is an unusual histological pattern of non-invasive neoplastic disease of the breast occurring predominantly in women aged between 40 and 50 years. LCIS is frequently multicentric and bilateral, and there is evidence that it is associated with an elevated familial risk of breast cancer. Although women with LCIS suffer an increased risk of invasive breast disease, this risk is moderate suggesting that LCIS may result from mutation of a gene or genes conferring a high risk of LCIS, but a lower risk of invasive breast cancer. The high frequency of somatic mutations in E-cadherin in LCIS, coupled with recent reports that germline mutations in this gene can predispose to diffuse gastric cancer, raised the possibility that constitutional E-cadherin mutations may confer susceptibility to LCIS. In order to explore this possibility we have examined a series of 65 LCIS patients for germline E-cadherin mutations. Four polymorphisms were detected but no pathogenic mutations were identified. The results indicate that E-cadherin is unlikely to act as a susceptibility gene for LCIS. © 2000 Cancer Research Campaig
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